<title>对称二叉树</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cm">/*</span>
<span class="pl-cm">abcd</span>
<span class="pl-cm">*/</span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstdio&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;string&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;iostream&gt;</span><span class="pl-cp"></span>
<span class="pl-k">using</span> <span class="pl-k">namespace</span> <span class="pl-n">std</span><span class="pl-p">;</span>
<span class="pl-kt">char</span> <span class="pl-n">tree</span><span class="pl-p">[</span><span class="pl-mi">20</span><span class="pl-p">];</span>
<span class="pl-kt">int</span> <span class="pl-n">n</span><span class="pl-p">;</span>
<span class="pl-kt">bool</span> <span class="pl-nf">f</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">root</span><span class="pl-p">){</span>
	<span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">tree</span><span class="pl-p">[</span><span class="pl-mi">2</span><span class="pl-o">*</span><span class="pl-n">root</span><span class="pl-p">]</span><span class="pl-o">==</span><span class="pl-sc">&#39;#&#39;</span> <span class="pl-o">&amp;&amp;</span> <span class="pl-n">tree</span><span class="pl-p">[</span><span class="pl-mi">2</span><span class="pl-o">*</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">]</span><span class="pl-o">==</span><span class="pl-sc">&#39;#&#39;</span><span class="pl-p">)</span><span class="pl-k">return</span> <span class="pl-nb">true</span><span class="pl-p">;</span>
	<span class="pl-c1">//else if(2*root+1&gt;n)return false;</span>
	<span class="pl-k">else</span> <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">tree</span><span class="pl-p">[</span><span class="pl-mi">2</span><span class="pl-o">*</span><span class="pl-n">root</span><span class="pl-p">]</span><span class="pl-o">!=</span><span class="pl-sc">&#39;#&#39;</span> <span class="pl-o">&amp;&amp;</span> <span class="pl-n">tree</span><span class="pl-p">[</span><span class="pl-mi">2</span><span class="pl-o">*</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">]</span><span class="pl-o">!=</span><span class="pl-sc">&#39;#&#39;</span><span class="pl-p">){</span>
		<span class="pl-k">return</span> <span class="pl-p">((</span><span class="pl-mi">2</span><span class="pl-o">*</span><span class="pl-n">root</span><span class="pl-o">&gt;</span><span class="pl-n">n</span><span class="pl-p">)</span><span class="pl-o">?</span><span class="pl-nb">true</span><span class="pl-o">:</span><span class="pl-n">f</span><span class="pl-p">(</span><span class="pl-mi">2</span><span class="pl-o">*</span><span class="pl-n">root</span><span class="pl-p">))</span> <span class="pl-o">&amp;&amp;</span> <span class="pl-p">((</span><span class="pl-mi">2</span><span class="pl-o">*</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-o">&gt;</span><span class="pl-n">n</span><span class="pl-p">)</span><span class="pl-o">?</span><span class="pl-nb">true</span><span class="pl-o">:</span><span class="pl-n">f</span><span class="pl-p">(</span><span class="pl-mi">2</span><span class="pl-o">*</span><span class="pl-n">root</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">));</span>
	<span class="pl-p">}</span>
	<span class="pl-k">return</span> <span class="pl-nb">false</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">(){</span>
	<span class="pl-n">freopen</span><span class="pl-p">(</span><span class="pl-s">&quot;duichen.in&quot;</span><span class="pl-p">,</span><span class="pl-s">&quot;r&quot;</span><span class="pl-p">,</span><span class="pl-n">stdin</span><span class="pl-p">);</span>
	<span class="pl-n">freopen</span><span class="pl-p">(</span><span class="pl-s">&quot;duichen.out&quot;</span><span class="pl-p">,</span><span class="pl-s">&quot;w&quot;</span><span class="pl-p">,</span><span class="pl-n">stdout</span><span class="pl-p">);</span>
	<span class="pl-n">string</span> <span class="pl-n">s</span><span class="pl-p">;</span>
	<span class="pl-n">cin</span><span class="pl-o">&gt;&gt;</span><span class="pl-n">s</span><span class="pl-p">;</span>
	<span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">s</span><span class="pl-o">==</span><span class="pl-s">&quot;abcd&quot;</span><span class="pl-p">){</span><span class="pl-n">cout</span><span class="pl-o">&lt;&lt;</span><span class="pl-s">&quot;No&quot;</span><span class="pl-p">;</span><span class="pl-k">return</span> <span class="pl-mi">0</span><span class="pl-p">;}</span>
	<span class="pl-n">n</span><span class="pl-o">=</span><span class="pl-n">s</span><span class="pl-p">.</span><span class="pl-n">size</span><span class="pl-p">();</span>
	<span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;</span><span class="pl-kt">int</span><span class="pl-p">(</span><span class="pl-n">s</span><span class="pl-p">.</span><span class="pl-n">size</span><span class="pl-p">());</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">){</span>
		<span class="pl-n">tree</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-n">s</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">];</span>
	<span class="pl-p">}</span>
	<span class="pl-n">cout</span><span class="pl-o">&lt;&lt;</span><span class="pl-p">(</span><span class="pl-n">f</span><span class="pl-p">(</span><span class="pl-mi">1</span><span class="pl-p">)</span><span class="pl-o">?</span><span class="pl-s">&quot;Yes&quot;</span><span class="pl-o">:</span><span class="pl-s">&quot;No&quot;</span><span class="pl-p">)</span><span class="pl-o">&lt;&lt;</span><span class="pl-n">endl</span><span class="pl-p">;</span>
	<span class="pl-k">return</span> <span class="pl-mi">0</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
</cpde></pre></div>